The present invention relates to accumulators for portable electric appliances.
Along with the demands for portable-type electric appliances such as lap-top computers and compact word-processors, it is desired to decrease the sizes and the weight of the portable appliances. The power sources of such portable appliances are for example dry cells. A dry cell may, however, accidentially cause the user to run out of energy on the way during his business. This may be a serious trouble if his business is very urgent. Moreover, it is an environmental problem where and how to discard exhausted cells.
Alternatively, built-in solar cells have been used in pocket electric calculators for example. However, the energy produced by such a built-in solar cell is not so large and therefore the application thereof is limited only to relatively small and low power consuming devices.